In venting, what can too high of a temperature rise across the heat exchanger lead to?

A high temperature rise across the heat exchanger can lead to condensation formation. When the temperature of the flue gases increases significantly, it can exceed the temperature at which water vapor in the gases begins to condense. This condensation can occur within the venting system as the cooler pipe surfaces come into contact with the hot, moist gases.

The formation of condensation in the venting system is problematic because it can lead to a variety of issues, including corrosion of the venting materials, decreased efficiency of the heating system, and potential blockages that impair the safe expulsion of flue gases. Proper venting requires maintaining appropriate temperature differentials to prevent condensation while ensuring safe and efficient operation of the heating system.